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.\" Copyright (c) 2018 Ian Lepore <ian@freebsd.org>
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.Dd July 9, 2018
.Dt IMX_SPI 4 arm
.Os
.Sh NAME
.Nm imx_spi
.Nd device driver for the NXP i.MX family Serial Peripheral Interface (SPI)
.Sh SYNOPSIS
To compile this driver into the kernel,
place the following line in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device imx_spi"
.Ed
.Pp
Alternatively, to load the driver as a
module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
imx_spi_load="YES"
.Ed
.Sh DESCRIPTION
The
.Nm
driver provides support for the
.Sq ECSPI
(Enhanced Configurable SPI) hardware present on the NXP i.MX family
of processors.
While the ECSPI hardware supports both master and slave mode,
this driver currently operates only in master mode.
.Pp
Due to hardware quirks, the
.Nm
driver requires that all chip select pins be configured as GPIO pins.
Use the FDT property
.Sq cs-gpios
to specify which pins to use as chip selects.
You may use any GPIO pins, including the ones that the hardware would
normally use as SPI select pins; just configure them as GPIO in the
.Xr fdt_pinctrl 4
data.
.Pp
.Sh SYSCTL VARIABLES
The following variables are available via
.Xr sysctl 8 ,
and as
.Xr loader 8
tunables:
.Bl -tag -width indent
.It Va dev.imx_spi.%d.debug
Output debugging info when non-zero.
A value of 1 displays information about bus transfers,
2 adds information about bus clock frequency and chip select activity,
and 3 adds information about interrupt handling.
.El
.Sh SEE ALSO
.Xr fdt 4 ,
.Xr fdt_pinctrl 4 ,
.Xr sysctl 8
.Sh HISTORY
The
.Nm
driver first appeared in
.Fx 12.0 .
